This invention relates to semiconductor devices manufactured by using a TAB tape, and more particularly to an improvement of the TAB tape.
A tape for TAB (Acronym for Tape Automated Bonding) is made by in sequence cutting from a base tape of plastic a rectangular or square opening, as a device hole, somewhat larger than a semiconductor chip to be mounted, putting copper foil over this plastic tape, and then etching this copper foil to form a lead pattern (Ref. Japanese Patent Laid-Open Application No. Sho. 58-15252). Inner leads project as if they were fingers inwards the device hole, and their end portions are bonded, accordingly connected, to bumps on a semiconductor chip placed in the device hole.
In general, the above-mentioned device hole in such TAB tape measures to receive the semiconductor chip therein with a gap of 0.5 to 1.5 mm. In the process of manufacturing semiconductor devices by using such a TAB tape, usually for the purpose of holding the reliability, coating with a resin such as an epoxy resin, following the above bonding step, is performed over the semiconductor chip and the projected portions of the inner leads inwards the device hole to form the resin coating on them for the protection of their surfaces (Ref. Nikkei Electronics No. 506 (Aug. 6, 1990) p. 113). After forming the protective resin coating, the TAB tape is wound on a reel, which then is set in an outer lead bonding apparatus. After bonding there, the outer leads are cut at their appropriate positions from the base tape, and bonded to a package, a printed circuit board or the like. Thus a semiconductor device is made up.
In the formation of the above-mentioned resin coating using the above-mentioned TAB tape, a part of the resin trends to drip through gap between the device hole edges and the semiconductor chip particularly at the corners of the device hole because of relatively large gap thereat. It, therefore, is difficult to form uniformly the above-mentioned resin coating. This brings an important problem particularly when a low viscosity resin is used as the coating material.